Collapsible well drilling bit



Oct. 23, 1934. C. 1 WALKER COLLAPSIBLE WELL DRILLING BIT Original Filed May 11, 1932 2 Sheets-Sheet l IN VEN TOR.

ATTORNE S.

C. L. WALKER COLLAPSIBLE WELL DRILLING BIT Oct. 23, 1934.

Original Filed May l1, 1932 2 Sheets-Sheet 2 Patented Oct. 23, 1934 UNITED i STATES,

PATENT OFFICE A 1,978,119 l ooLLAPsILE WELnnmLLrNG BIT Clintonl L. Walker, Piedmont,E Calif; original applicati@ May 11,` '1932, serial'N'o.h 610,633.' Divided and this,applicationNovem-` ber 7, 1933, serial-Nq. 6196.966 j 4, Claims. (Cl..255-74) 'I his application is a division of `my co-pending application entitled Deep well drilling and coring system, led May 1l, 1932, and bearing Serial No. 610,633.

This invention relates towell drilling equipment, and particularly .pertains to an improved rotary drilling bit for advancing deep well bores by the rotary-method. l

It is the principal object of the present invention to provide an improved collapsible rotary drilling bit of the character referred to which may be expeditiously assembled on a drillstem at the bottom of the bore, or removed therefrom without the necessity of removing the drill stem from the bore.

In practising the invention, I have provided a collapsible rotary drilling bit which may be run in through the drill stem and readily assembled on the lower end ofthe drill stem so thatthe proper weight can be imposed on, and proper torque applied to, the bit through the drilling stem to effect thedrilling operation. The bit is also capable of beingdisconnected from the drill stem whilethe same remains in the bore and removed upwardly through the drill stem in order that bits maybe replaced on the drill stem without removing the latter from the bore. When my improved drilling bit is utilized, there is no necessity of removing the drilling stringfrom the bore until the drilling operation is entirely complete and the bore is ready for casing.

One form which the invention may assume is exemplified in the following description and illustrated by way of example in the accompanying drawings, in Which Fig. 1 is a view in Vertical section through' a .well bore, showing the drill stem disposed therein with my improved drilling bit assembled vthereon for operation;

Fig. 2 is a view in vertical section through the lower end of the drilling stem, showing the position which the bit assumes when it is beinglowered or elevated through the drill stem;

Fig. 3 is a view in vertical section through a well bore, showing the drill stem disposed therein with my improved drilling bit assembled thereon for operation, this gure being taken at 90 to Fig. 1; and

Fig. 4 is a transverse sectional view taken on line IV-IV of Fig. 3. I

Referring more particularly to theaccompanying drawings, in Figs. 1 and 2 I haveillustrateda well bore 10 within which .a drill stem or drilling string l1 is suspended. The upperend of this 5 5 drilling string in practice is tted with a kelly bar and operatively connected with a rotary drill tablefor operation. It is.- of course, also associated with a rotary hose and draw works, but as all of this is standard practica-it is noty illustrated.

The lowerend of the drilling stringbr drill stem is fitted withwhat I preferto term -adrilling shoe 1.2, the `interrlal ;l ia.r r1eter of-which agrees with the internal diameterof the drillstem proper. At its lower endthedrilling shoe 1'2 isformed with two opposed slots 1 4 which yproject upwardly from 65 the lower teijmi nal of the drilling shoe 12.

'I he presentinvention contemplates the provisionof aollaps'ible drilling bit which agrees somewhat in form withvthe f1sh tail type of drilling bit utilized in rotarydrilling practice. It is to be understood'that although the fsh-tail type o f bit vis .illustrated'mybit may assume the form o f aroclrVv or roller cutter bit withoutdeparting fromy theinverltion."

Due to the fact t` at the bit here illustrated and described is'collapsibla'it may-bey lowered through thedrillinggstringand beivla'ss'embled for operation vat thev lower lend `o f the ,drill .stem or vdisconnected from the latter and 'elevated therethrough-without thefnecessity Vof removing the drillsteinfrom the bore. When the bit is connectedtothelower end of the drill stem for operation; theconnection such that the weight of the drill`s`tem may be imposed on thebit and torque'trans'mitted from the drilling string to the bit in order ,to 4accomplish the drilling operation. The ffcm' o f. thebit which I have illustrated includes allofll'o'w bit body 15 Within which is mountedvapairof atb'lades 16. These blades are pivotally disposed` on' a transversely arranged pintle 17., .supported at its` ends in the hollow b it body1 5'. T- he bit' body,-15 is substantially cylindricall in extrnal contour and is of an external diameter enabling it to be freely reciprocated within the drilling string 11. The pivotal point ofthe blades 16 Ais located substantially centrally between'the'upperand lower ends of the blades.

It will be noticed that the lower ends of the blades 16 are'fla'red outwardly and are provided with cutting lower and sideedges. The blades 16 areeach provided with a lateral shoulder 18 at a point just above the flared lower ends. When the flared lower ends of theblades 16 are projected radially outwardly throughI the slots 14 in the drilling shoe 12, theshoulders 18 engage the top of the slotsl4 so as 'to form an abutment through which the weight of the drill stem may be imposed ontheblades. Asthe flared ends of the blades project through the slots 14, a keyed or torque-transmitting connection is provided between the blades and the drilling string in order that torque may be transmitted from the drilling string to the blades.

At their upper ends, the blades are connected to toggle links 19, which links are connected together centrally between the upper ends of the blades and at this point they are connected toa vertical link 20. The link is pivotally connected to the lower end of a trip member 21, which is mounted for reciprocation co-axally of the body 15 in the upper head of the body. When this trip member 21 is moved to its uppermost position, a toggle action will result which will collapse the bit by drawing the 'upper ends of the blades 16 toward each other and consequently withdraw the lower ends of the blades 16 to a position where they may freely pass through the drill stem, as is illustrated most clearly in Fig. 2.

Coil springs 22 are provided and arranged within the body 15 and connected at their upper ends to the toggle mechanism at the point of connection ybetween the toggle links 19. The lower ends of the springs 22 are anchored to the hollow body 15, as 'most clearly 'illustrated in Fig. 3. 'It is obvious that inasmuch as these springs 22 exert a l'constant downward pull on the toggle mechanism, they will constantly tend to maintain the drilling bit expanded to drilling position.

` passageways 24 to the Acutting surfaces at the lower ends of the blades.

In order properly to -position my improved 'bit at the VVbottom of the drilling string, the -same may be run downwardly through the drilling l'string von l a cable, as illustrated in dotted line in Fig.'1; or

it 'may be forced to this position by means of a method and apparatus described and claimed in my co-pending application entitled Drilling 'apparatus, led November 7th, '1933, 'Serial No. 696,967.

It will be no'ticed that the drillings'hoe 12`is provided with an internal annular shoulder 25 at the lower end, against which the lower endof the hollow drill body 15 will abut when the bit is `positioned properly for 4expansion toa drilling position. To collapse the bit and withdraw it from the drilling stem, la pull may be exerted on the trip member 21 either through the medium of a cable, as illustrated in dotted lines in Fig. 1, or

- through the medium of an apparatus such as described in my co-pending application just referred to. It will suihce to say that when an upward pull is exerted on the trip member 21, the springs 22 will first be overcome through the toggle mechanism and the latter willcause the upper ends of the blades to move toward each other. This movement will withdraw the lower ends" of the blades to a position disengaging them from the Aslots 14 and enabling them to pass upwardly into the drill stern. When the trip member 21 has been moved upwardly to the limit of its movement, a continued pull thereon will move the drill body 15, "together with the blades 16, upwardly through the drilling string.

Inthe operation of the bit, yit -is-lowe'red downwardly through the drilling string, assuming, of course, that the latter is in place in the bore, either by means of a cable or otherwise. During the lowering movement the blades 16 will be in a collapsed condition so that they may pass downwardly through the string. As the hollow drill barrel carrying the blades 16 reaches the lower end of the drilling string, yand is positioned in the drilling shoe 12, two spring pressed dogs 26, which are mounted at the exterior of the hollow drill body 15, will engage helical grooves 27 formed in the bore of the drilling shoe 12. Engagement of the dogs 26 with these grooves will cause the blades 16 to properly register with the slots 14 in the drilling shoe when the latter reach the proper position forexpan- Sion. When the blades come in register with the slots 14 and the lower end of the drill barrel engages the internal shoulder 25, the springs 22 will cause the bit to expand and the blades 16 will move radially outwardly through the slots 14 with the shoulders 18 on the blades abutting the tops of the slots 14, as illustrated in Fig. 1.

Engagement of the blades 16 with the slots 14 completes a weightand torque-transmitting connection between the blades and the drilling string, and the bit '-is then ready for operation.

Should the bit become dull or if, for any other reason, it should be desired to replace the bit, an upward pull is exerted on the trip member 21 so that the same will move upwardly relative to the drill body 15. This movement of the trip member will be accompanied by collapsing ict of the bit or radial inward movement- -of the blades 16. When the trip member reaches the upper limit of its movement relative to the drill body 15, 'a -further pull exerted thereon will vcause the drill body 15 'and the blades 16 carried thererie by to move upwardly through the drilling string.

It is obvious from the foregoing that my improved -drilling bit may vbe replaced expeditiously when it becomes dull, or replaced -by a dif- 'ferent type bit, when 'a vdifferent formation is encountered, without the necessity of removing the drill stem from the well bore.

WhileI-have 'shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit 4of the invention as deiined in the appended claims.

Having described my invention, what I claim and desire to secure by Letters Patent is- 1. A drilling apparatus of the character described including a drill stem, a drilling lbit including a bit body, a pair of centrally pivoted blades, capable of relative `pivotal movement mounted in the -body, a toggle mechanism connecting the upper ends of the blades, spring means yconnecting the toggle mechanism to the body and constantly tending relatively to expand the blades .through the toggle mechanism.

2. A drilling apparatus of the character described lincluding -a drill stem, a drilling bit including a Ebit body, a pair of centrally pivoted blades capable of relative pivotal movement mounted in the body, a toggle mechanism connecting the upper ends of the blades,v spring means connecting the toggle mechanism to the body and constantly tending relatively to expand the blades-through the toggle mechanism, and complemental means on the bit and drill stem vforming 'a weightand torque-transmitting connection between Ithe Vsternand bit when the latter is positioned and expanded for'operation at the lower end of the stem.

3. A drilling apparatus of the character described including a drill stem, a collapsible drilling bit including a bit body, a pair of centrally pivoted and relatively movable blades mounted in the body, a toggle connection between the upper ends vof the blades, spring means connecting the toggle connection to said body and constantly tending to move the lower ends of the blades radially outward through the rtoggle connection, means connected with said toggle conerly positioned at the lower end of the stem,

said bit being capable of passing through the stemk when the bit is collapsed.

4. A drillingl apparatus of the character described including a drilling stem, a collapsible drilling bit including a hollow cylindrical bit body of a diameter somewhat less than the internal diameter of the drilling stem, a pair of centrally pivoted blades carried by the bit body, a toggle connection between the upper ends of the blades, spring means interposed between the toggle connection and the bit body and constantly tending to move the lower ends of the blades radially outward in opposition to each other, a member carried by the bit body and projecting above the upper end thereof and connected with said toggle connection to cause relative radial inward movement of the lower ends of the blades when an upward pull is exerted on said member, said drill stem having slots formed in its lower end through which said blades `are adapted to project when the blades are moved radially outward, and means for positively placing said blades in 'register with said slots when the bit has been lowered in the drill stem to operative position relative to the stem, said bit being capable of passing through the drill stem when the blades are moved to their innermost position.

CLINTON L. WALKER. 

